The current structure associated with fluid tanks in service stations comprises a storage tank having a fill pipe disposed below a manhole for the reception of fluids to be used at the pumps. Also included are various venting means and vapor recovery systems to be sure that the pressure within the storage tanks does not become excessive nor do the vapors re-enter the atmosphere.
Patents which fall within these classifications comprise the following five:
U.S. Pat. No. 2,564,871 Wikman PA1 U.S. Pat. No. 3,633,219 Byrd PA1 U.S. Pat. No. 3,662,794 Turner PA1 U.S. Pat. No. 3,908,718 Bower PA1 U.S. Pat. No. 4,094,346 Milo
Curiously, however, none of these patents contemplate nor provide for the situation where the main storage tank has been filled to the maximum capacity and there is still a quantity of fluid within the hose that extends from the transport truck to the standpipe. Human nature being what it is, and given the fact that the transport truck uses gravity feed into the main storage tank, the excess fluid within the hose is usually disposed of by shutting off the valve at the transport truck and disconnecting the coupling between the hose and the standpipe. This of course causes the fluids to run around the storage tank and into underground streams around sewer conduits, etc., and in general, deposits this fluid into the ground. Therefore, these liquid fuels seep into the ground to underground natural drainage systems or overflow into storm drains eventually flowing into rivers or other natural waterways. In addition, however, such fluids that eventually flow into natural waterways pollute. Some, of course, will evaporate and therefore, pollute the air.
Equally objectionable is the volatility of these fluids which, should they migrate to certain areas, provide fire hazards. For example, such fluids have been known to seep into the basements of adjoining buildings and be ignited by machinery located in boiler rooms, etc.
Further, the necessity of conserving these liquids has become more critical to such an extent that such waste is no longer tolerable.